Motor-testing chamber



Filed July 2. 1920 INVENTORZ Patented .luly29, 1924.. I

LUDWIG- DI'TER, or rrtrnnarcnsnarnn, G RMANY; ASSIGNOH. To- THE FIRM: LUFT- SCHIFFBAU ZEPPELIN e-nsELLsoHArr MIT BESGHRANKTER I-IAFTUNG, or FRIED- RICHSHAFEN, GERMANY.

' MO'I'OR-TESTING'CHAMBERL Application filed July 2,

.T 0 all whom it may concern:-

Be it known: that I, LUow-rG Dr'inn, a citizen of the German Empire, residing at Friedrichshafen, Germany, have invented certain new and useful Improvements in Motor-Testing Ghambers (for which'I have filed application in Germany January 29, 1917), of which the. following is specification.

My invention refers to the testingof internal combustion motors and moreespecially to a chamber serving for the testing of motors for-aviation purposes and being adapted to be closed air-tightly so that a reduced pressure can be produced in its interior.

In order to test aviation motors in an absolutely reliable manner it is necessary to create by artificial means the atmosphericalconditions, substantially consisting in a reduction of the air pressure, without however injuriously influencingor changing the natural flow of the air nor the other con ditions of working of the motor. It is of special importance to maintain under all circumstances at the exhaust pipe and the other parts of the motor as well as within the interior of the chamber a more or less reduced, but always the same pressure. Of equal importance as being characteristic for an aviation motor working in the free atmosphere is the absence of exhaust gases in the proximity'of the air inlets.

According to the present invention, now, all this is attained by means of an exhaust fan adapted to remove not only the entire exhaust gases but also part of the air from within the chamber.

My invention therefore consists ina testing chamber provided with a high power exhaust fan for removing the exhaust gases. According to my invention the suction pipe is further provided with openings serving for effecting a connection with the interior of the chamber and thereby providing that the pressure prevailing at the exhaust valve and the other parts as well as in the interior of the chamber is the same. As the exhaust fan can carry away more than the maximum of exhaust gases available, every danger of the Said gases accumulating or striking back into the interior of the chamber is avoided. The openings of the 1920. SerialNo. 393,754.

suction pipe communicating with the interior of the chamber prevent the exhaust piping to be evacuated unduly to a greater extent than the interior of the chamber;

By suitably constructing the exhaust box fresh cooling air may easily be sucked infor: the exhaust gases which are quickly passingthrough it.

It is a: further object of. my invention to provide within the testing chamber a reducing valve adapted to-begoverne'd, there,- by causing, the predetermined reduced pressure to be obtained automatically for; any

length of time independently of any varia- V tions in output of the fan or the motor which might arise during the test. Thus, in order to'maintain this 'reducedpressure there is neither wanted a regulation of the quantity of air Iiowin in, nor a regulation of the number of revolutions of the fan nor one of the motor output. Nor is there any obligation to carry out the test with a predetermined motor output such as for in stance the maximum output. Furthermore the desired temperature within the chamber can thus be maintained in an especially simple manner. For provided that the walls of the chamber are not only air tight but are also bad conductors of heat, and that the reducing valve be suitably dimensioned, the cooling down, due to expansion, of the fresh air entering through the reducing valve can be fully utilized. It is therefore possible to obtain the low temperatures prevailing at high altitudes without being compelled to resort to a larger air cooling device.

In the drawings afiixed to this specification and forming part thereof a testing chamber constructed in accordance with my present invention is illustrated by way of example, the diagram showing a horizontal section of a simple evacuation chamber with a motor arranged therein.

2 Referring to the drawings, A is the chamber closed on all sides andhaving walls made of reinforced concrete with a double door a arranged therein. B is the motor whose cylinders are connected to a common exhaust box C. In order to increase the exhaust action and to cool the exhaust gases inthe simplest manner, the exhaust box whose outlet portion is reduced after the manner of a nozzle, is surrounded by atubular acket D having one end communicating freely with the chamber A, while its other end is connected with the suction head a of the fan E. The suction head 6 communicates directly with the interior of the chamber by means of inlet openings 6 which are preferably provided with flap valves adapted to open as soon as the pressure within the head 6 has fallen to a small predetermined extent below the pressure within the chamber. between the exhaust box C and the jacket D be sufliciently large, the special inlet openings 6 might even be dispensed with. A pressure pipe 6 of the fan E leads into the atmosphere. The desired reduced pressure is maintained within the chamber by means of a reducing valve F provided therein and which may be adjusted to any desired re duction, the suction pipe of said valve being traversed by fresh air whenever the reduction of air within the chamber is likely to exceed the predetermined value.

I claim:

Provided the interstice 1. In a motor testing plant in combination, a closed chamber designed to take up the motor to be tested a high power exhausting device in said chamber having openings in the exhaust piping for establishing a communication between the interior of said piping and the interior of said chamber and means for establishing a connection between the exhaust side of said motor and the intake of said exhausting device.

2. In a motor testing plant in combination, a closed chamber designed to take up the motor to be tested, a high power er hausting device in said chamber having openings in the exhaust piping for establishing a communication between the interior of said piping and the interior of said chamber and means for establishing a connection between the exhaust side of said motor and the intake of said exhausting device, and a reducing valve, communicating with the outer air.

In testimony whereof I afiix my signature.

LUDWIG DURR. 

